Edge Online has a Q&A with Blizzard's Bob Colayco about the revelation that
StarCraft II will be released as three different products. Bob flatly
denies that this is a pernicious effect of the Activision Blizzard merger and
also decries accusations they are trying to milk the science fiction RTS
franchise: "Activision doesn’t really factor in, because ultimately the people
calling the shots on how this game is going to turn out is the StarCraft II dev
team. This trilogy decision was really made by that team. Effectively, what are
we really talking about here? We’ve always done our RTS games with one expansion
pack. So now we’re releasing two. Is it really that weird?"

Well, not every expansion is created equal, so standard pricing is kind of hard. I see EA's expansions for the Sims as complete ripoffs, so I don't buy them for my daughter. Valve's expansions (you can call the episodes but it's really semantics) were priced differently, but The Episode 2 package with Portal and TF2 was an infinitely better value at 40 bucks than Episode 1 was at 20 bucks. Then there are the expansions for the total war series, which are 30 bucks and provided up to a hundred more hours of play time. I have spent about 70 hours on the Teutonic and Crusades campaigns alone for TW Kingdoms. It would be hard to pinpoint a price for the SC 2 expansions without seeing the amount and quality of the content.

“The greatness of a nation and its moral progress can be judged by the way its animals are treated.” - Mahatma Gandhi